Most of the videos are copyrighted, and los of countries are blocked from viewing them, overall this site is useless because all you can watch are "fun" videos made by some kids. Unless you are from the USA you cant really enjoy it.
Yes it's an entertaining site, but more adult content. More hateful, violent, illegal content, xenofob content. One hateful content you see here: http://www.youtube.com/watch?v=D7l4kkHHxfU&feature=related
Good website that is generally child safe and free of garbage. Occasionally the moderation can be slow at removing bad things but on the grand scheme it's as safe as or safer that other websites that rely on a community or aggregate content.